238 Forestry Quarterly. 



This reserve cellulose is claimed to be deposited in different 

 tissues in different species — in the primary cortex and phloem of 

 twigs, in the phloem and xylem of older stems and roots. The 

 increase in thickness and density of membranes is said to take 

 place in the latter part of summer and in autumn, and the thin- 

 ning to take place when growth starts in the spring. 



OBSERVATIONS. 



An examination of nine of our representative forest trees was 

 made at intervals of one to two weeks from the first of October, 

 1905, to the middle of June, 1906. This study was undertaken 

 with a view to gaining further information on two questions : 

 (i) How closely do our trees conform to the behavior of their 

 near relatives in Europe? (2) There having been heretofore 

 relatively but few trees examined for the determination of the sea- 

 sonal variation of the carbohydrates in the roots, what is the con- 

 dition of these reserves through the seasons? 



The methods employed were simple, being merely a microscop- 

 ical examination of sections treated with iodine, Fehling's 

 solution, osmic acid, alkannin, or cyanin. These reagents, of 

 course, identified only the starch, reducing sugar, and fats. Un- 

 fortunately time did not allow the determination of the reserve 

 cellulose, nor any more accurate measurements of the starch, 

 sugar, and fat than could be judged by simple observation of 

 sections. 



In making the observations here recorded, 9 trees were ex- 

 amined : Populus deltoides Marsh., Tilia americana L., Salix alba 

 L., Juniperus virginiana L., Ulnius americana L., Acer saccharum 

 Marsh., Quercus rubra L., Juglans nigra L. and Carya glabra 

 Mill. All of these trees grow wild in this region, and all except 

 Salix are native. 



A glance suffices to show that of the 9 trees, the first 3 in the 

 list are soft-woods, and the 4th a gymnosperm, and hence the 

 four belong to the group whose relatives in Europe are said to 

 dissolve all or the most of their starch above ground in winter, 

 while the last 5 belong to the group whose European relatives 

 have been found by most observers to dissolve the starch above 

 ground in the cortex and phloem but to retain more or less starch 

 in the xylem throughout the winter. 



